Abstract 16617: Dendritic Cells Primed with apoB-100-derived Peptide p210 Elicit a CD8+CD25+ T cell Response
We have reported that vaccination with apo B-100 related p210 peptide significantly reduces atherosclerosis in apoE-/- mice; this effect appears to be mediated by CD8+ T cells through interaction with dendritic cells (DCs). In this study, we investigated the potential of p210-primed DCs to activate naïve T cells in vitro.
Methods and Results: Naïve whole splenocytes were co-cultured with LPS-matured, p210-primed bone marrow derived DCs (LPS-p210-DC) and the T cell populations were characterized by flow cytometry. Untreated DCs (control) and LPS-treated DCs (LPS-DC) served as controls. Co-incubation of whole splenocytes with LPS-DC and LPS-p210-DC significantly increased CD4+CD25+ T cells compared to control. On the other hand, co-incubation of whole splenocytes with LPS-DC induced only a modest increase in CD8+CD25+ T cells whereas CD8+CD25+ T cells were further significantly increased in the LPS-p210-DC co-culture, suggesting a CD8+ T cell response specific to p210. To confirm this response to p210 by CD8+ T cells, the co-culture experiment was repeated with CD8+CD25- T cells isolated from spleens of naïve mice. Co-culture of CD8+CD25- T cell sub-population with LPS-p210-DCs resulted in significantly increased CD8+CD25+ cells compared to control DCs and LPS-DCs, consistent with the whole splenocyte co-culture results. To further elucidate if cell-to-cell contact is required for p210-primed DCs to elicit such CD8+ T cell response, we assessed the role of exosomes in T cell : DC interaction. Conditioned medium of control, LPS, and LPS-p210-DC cultures were subjected to sequential high speed centrifugation to collect exosomes which were characterized by immuno-blotting. Exosomes were then co-incubated with splenocytes collected from naïve mice. There was no difference among the groups sourced for the exosomes.
Conclusion: Our studies support the potential of p210 to elicit CD8+ T cell response, possibly via cell-to-cell contact.
- © 2012 by American Heart Association, Inc.